<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title></title>
	<style>
		::-moz-selection {
			background-color: #f90;
		}
		::selection {
			background-color: #f90;
		}
		/* not work */
		::-moz-selection:-moz-window-inactive {
			background-color: blue;
		}

		/* not work */
		:-moz-window-inactive::-moz-selection {
			background-color: blue;
		}

		::selection:window-inactive {
			background-color: blue;
		}
	</style>
</head>
<body>
	<h1>请全选网页，然后，点击浏览器之外，让浏览器失焦！</h1>

	<ol>
		<li>
			<a href="https://css-tricks.com/window-inactive-styling/" target="_blank">Window Inactive Styling</a>
		</li>
		<li>
			<a href="https://developer.mozilla.org/en-US/docs/Web/CSS/:-moz-window-inactive" target="_blank">:-moz-window-inactive</a>
		</li>
	</ol>
</body>
</html>